As the density of a semiconductor device becomes higher, the importance of technologies such as multilayer wiring, and formation of interlayer insulating films and electrodes (such as a plug and a damascene structure) associated with the multilayer wiring is increasing. At the same time, the importance of planarization processes of the interlayer insulating films and the electrode metal films is increasing. As an efficient technology for the planarization processes, a polishing technology called CMP (Chemical Mechanical Polishing) is widespread.
The CMP apparatus generally includes a polishing head that holds a semiconductor wafer as a subject to be processed, a polishing pad for performing a polishing process of a subject to be processed, and a polishing platen that holds the polishing pad. In a polishing process of a semiconductor wafer using a slurry, a semiconductor wafer and a polishing pad move relative to each other, so that projections of a semiconductor wafer surface layer are removed to planarize the wafer surface layer. A pad surface is updated by dressing with a diamond dresser and the like for clogging prevention and setting.
The polishing properties of CMP include various requirement properties represented by wafer local flatness, securing of global flatness, prevention of scratches, securing of a high polishing rate, and the like. Therefore, in order to achieve these, various designs are provided in a groove configuration (such as a groove pattern and a groove cross-sectional shape) of a polishing pad. The groove configuration is one of the largest factors affecting the polishing properties.
For example, there is known a technology to improve wafer flatness and a polishing rate by providing a groove that is arranged on a polishing layer surface and has a concentric circular pattern and a substantially rectangular cross-sectional shape (for example, see Patent Literature 1).
However, in this technology, corners in a cross-sectional shape of a groove and burr-like materials formed in the corners caused by dressings performed prior to, following to, or during polishing may sometimes cause generation of scratches. To solve this problem, there is disclosed a technology of providing an inclined surface at a boundary between a polishing surface and a groove (for example, see Patent Literatures 2 and 3).